1. Field of Invention
The present invention relates to broadband wireless access systems, and amongst other things to a method of dynamically scheduling multiple upstream channel transmission in a broadband wireless access system.
1. Discussion of Background
Point to multipoint fixed broadband wireless access systems over MMDS networks are known in broadcast situations. These networks operate over licensed bands including the MMDS band (2,150 to 2,162 MHz), the WCS band (2,305 to 2,360 MHz) and the ITFS/MMDS bands (2,500 to 2,686 MHz).
A known wireless broadband access system, which operates at a range of between 50 MHz and 864 MHz, but not in the MMDS, WCS, or ITFS/MMDS bands, is the data over cable specification system, which is specified in the data over cable system interface specifications (DOCSIS). An overview of a wireless DOCSIS system is depicted in FIG. 1. A CMTS 10 communicates with a wide area network 20, such as the internet. The CMTS 10 can transmit signals from the wide area network 20 along a cable network 30 through cable modems 40 to CPE 50 (Customer Premise Equipmentxe2x80x94intended throughout this document to include a computer and/or all of the equipment at the customer site, such as a LANxe2x80x94Local Area Network) . CPE 50 messages can be transmitted to the wide area network 20 through the cable modem 40 along the cable network 30 to the CMTS 10.
In point to multipoint broadband wireless access systems one central end-point, e.g. the head-end, communicates through a bi-directional link or links with multiple end-points, e.g. the nodes. The number of nodes in communication varies in time and can be none, one or two or more at any specific time.
The link(s) between the head-end and the nodes are combined in one or more channels. The signal path from the central endpoint to the nodes is referred to as downstream, while the signal path from the nodes to the central end-point is referred to as upstream.
A single upstream channel can be used to deliver information from a node to the head-end and a downstream channel is used from the head-end to a node or a group of nodes. If a single upstream channel is used for communication from the nodes(s) to the central point, then only one end-point can sends information on the single upstream channel at any one time.
Point to Multipoint Broadband-Wireless Access systems are typically asymmetrical with upstream channels operating at lower speeds than the downstream channels. The downstream channel(s) typically carry a continuous signal to all the CMs. This signals includes operational information (such as synchronization) that is necessary to establish the upstream channel. The establishment of the downstream communication is a precondition for the system to start the relatively complex and less reliable process of upstream communication. Problems can occur when there are failures in upstream communication while the more reliable downstream channel is still transmitting, this may lead to situations where there is downstream communication with a modem having non-operational upstream. This is a waste of downstream channel bandwidth and further causes problems for the user.
The Data Over Cable System Interface Specification (DOCSIS), Cable Modem To Customer Premises Equipment Specification SP-CMCI-I03-991115, defines that the CM may have self-diagnostic capability.
However, the CM can only have information about itself and has no knowledge regarding the rest of the network. Further, the processing and memory capability of the CM make it difficult to perform sophisticated diagnostics utilizing its own capabilities.
A present invention provides for remote maintenance and service of one or more wireless modems in communication with a wireless hub is provided. This includes the capability of the wireless hub to instruct the wireless modem(s) to change any operational parameters in order for the wireless hub to diagnose any problems with or to improve operation of the wireless mode. An additional feature of the present invention allows for the creation of predictive models based upon changes to the transmission characteristics of the wireless modem(s) based upon the changes to any parameters.
In one embodiment, the present invention provides for a system and method for communication between a wireless modem and wireless hub on a selected downstream channel of a plurality of downstream channels. The selected downstream channel is chosen by the wireless modem after receiving communication parameters for each of the downstream channels and choosing the selected downstream channel by determining the most efficient of the downstream channels at that time for downstream communication.
In another embodiment, the present invention provides for a system and method for communication between a wireless modem and wireless hub on one selected upstream channel from a plurality of downstream channels. The selected upstream channel is selected by the wireless modem after receiving communication parameters for each of the upstream channels and selecting the selected upstream channel by determining the most efficient of the upstream channels at that time for upstream communication. It is also possible that this embodiment, is combined with the first embodiment such that the plurality of upstream channels are associated with the selected downstream channel.
The present invention is embodied as a method for remotely testing a wireless modem in communication with a wireless hub, comprising, synchronizing a wireless modem with a wireless hub on a downstream channel of a plurality of downstream channels, receiving information at the wireless modem corresponding to a plurality of upstream channels that can be used to communicate from the wireless modem to the wireless hub, placing the wireless modem into a service mode, by transmitting from the wireless hub an instruction for the wireless modem to operate in the service mode, and testing at least one parameter of the wireless modem to determine the optimal channel for upstream communication from the wireless modem to the wireless hub. In addition, the invention includes A method for remotely servicing a wireless modem in communication with a wireless hub, comprising, transmitting from the wireless hub to the wireless modem a first information signal, receiving the first information signal transmitted from the wireless hub to the wireless modem at the wireless modem, transmitting from the wireless modem to the wireless hub a second information signal, failing to receive the second information signal transmitted from the wireless modem to the wireless hub at the wireless hub, transmitting an instruction from the wireless hub to the wireless modem instructing the wireless modem to operate in a service mode, operating the wireless modem in a service mode, and testing at least one of several parameters of the wireless modem to reestablish an upstream communication path from the wireless modem to the wireless hub. Still further, the invention includes a method of communicating with a modem having service mode capabilities, comprising the steps of, initiating a service mode in the modem, incrementally changing parameter values of said modem until an upstream channel communicated by said modem is acquired by a hub, and initiating another mode of operation.
The invention may also be embodied as a device (modem), comprising, a reception device configured to receive downstream communications from a hub, a service mode mechanism configured to identify a service mode request for the modem and place the modem in a service mode, and a service mode command mechanism configured to identify and perform service mode commands.
Both the modem and methods may be conveniently implemented on a general purpose computer, or networked computers, and the results may be displayed on an output device connected to any of the general purpose, networked computers, or transmitted to a remote device for output or display.